In general, a midplane is a centrally located circuit board structure which connects to other circuit boards on both sides. That is, the midplane is planar in shape, and defines a front side and a back side. Some circuit boards connect to the front side of the midplane. Other circuit boards connect to the back side of the midplane.
Such a midplane typically includes multiple conductive and non-conductive layers which are sandwiched together in order to provide a dense network of electrical connections between the connecting circuit boards. Accordingly, the circuit boards are capable of enjoying a high degree of electrical connectivity within a relatively small space.
Manufacturers typically pre-construct large frames for carrying such midplanes, and bolt these midplanes in the middles of the large pre-constructed frames. As a result, the midplanes divide the pre-constructed frames into two halves, namely, front card cages and rear card cages. Next, the manufacturers insert circuit boards into the front card cages until the circuit boards connect to front sides of the midplanes, and other circuit boards into the rear card cages until these other circuit boards connect to rear sides of the midplanes. The manufacturers are also capable of electrically connecting other components to the midplanes such as fans or power supplies using cables. In this manner, the manufacturers are capable of forming highly dense networks of electronic circuitry.